Conclusion: I ran these in a dodge ram for a friend pushed by an old school crossfire tek150. He originally had it pushed by a powerbass which sucked buttonholes but once we switched it out for the crossfire old school amp they really came to life. Clean sound. I ran the older ones in my acura rl for literally 8 years and never had to switch them out.
Conclusion: For the price there is no comparison!! You can't go wrong with these speakers, they sound AMAZING!!!! The tweeters are nice and smooth sounding, crystal clear. And the mids are great also!!! They have very good midbass. I set my amp crossover for 75hz and up.
Conclusion: Put these in the front of my 2010 Civic Ex-L as part of a total speaker replacement. Woofers are great. Word of warning with the tweeter components, though. I have a factory amp that apparently puts more power to the tweeters than other speakers. As a result, the 610C tweeters screamed so loudly it threw off my entire audio balance and ruined the quality. Best Buy's solution was rewire to bypass the amp or do a bunch of other expensive stuff.
Conclusion: Great sound. Obviously, it's tough for a 6.5" to match what you can get from a 6x9" in terms of deep sound or bass, but you've got to work with what fits in your car. Depending on the kind of bass, though, you will find yourself pleasantly surprised at how great the 610s and 610Cs sound. Put the 610s in the back dash of my 2010 Civic EX-L and the SPS-610C in the front. The 610s are great, no complaints.